A 28-year-old man was found dead inside his Harlem apartment with a black bag over his head and his hands bound behind his back — days after his landlord said he found him rolling naked on the floor, law enforcement sources said.

The victim’s landlord called police around 8:20 a.m., to report finding the man dead inside a first-floor apartment on St. Nicholas Avenue, sources added. The landlord told cops he hadn’t seen the victim since Friday, when he was naked on the floor, inside the five-story brownstone, sources said.

A neighbor said the man, who worked in a nursing home Uptown, seemed depressed and may have been on medication. He had also recently lost a lot of weight and was suffering from skin problems, neighbors said. Police found 10 prescriptions from three different doctors. They included oxycodone and amphetamines, sources said.

The victim’s brother killed himself after wiping out his whole family last year, sources added. The victim’s boyfriend moved to California after living with the victim for two years, sources said.

Aside from the rope binding the victim’s hands and the bag over his head, there were no immediate signs of trauma, sources said. The victim’s iPhone and other electronics appeared untouched inside his room and police are trying to get a warrant to search them, sources added.

Police have not released the man’s name. No arrests have been made. Cops are waiting for the Medical Examiner’s Office to determine a cause of death.

Van Kilpatrick, 65, grew up in the neighborhood and has watched it changing over the years:

“It is a very nice block,” he said. “It is completely gentrified. That building is very quiet. You only see people coming and going. There has been no complaints about anyone there.”